Recently, personal data assistant (PDA) and notebook are remarkably progressing. The demanded requirements of the displays for portable use are light weight and low power consumption. Thin film transistor-liquid crystal display (TFT-LCD) can meet the above requirements and is known as the display required for the high pixel density and quality. In general, the TFT-LCD includes a bottom plate formed with thin film transistors and pixel electrodes and a top plate formed with color filters. The liquid crystal is filled between the top plate and the bottom plate. In each unit pixel, a capacitor is provided which is formed by virtue of the TFT serving as the switching element of the unit pixel. When the data voltage is applied to the TFT, the arrangement of the liquid crystal molecules is change, thereby changing the optical properties and displaying the image.
In general, the viewing angle and the color performance are very important issues for the design of the LCD. A color filter (CF) plate is used in the LCD to show the colored portion of the screen. One of the trends for the LCD technology is to improve the viewing angle of the LCD. However, the viewing angle and contrast ratio of LCD are still insufficiently applied to products having large screen. One of an article relating to a vertical-alignment-mode LCD can be seen in SID'97 DIGEST p845.about.p848, proposed by K. Ohmuro, S. Kataoka, T. Sasaki and Y. Koike. In the reference, the VA-LCD(vertically aligned LCD) has been implemented by optimizing a vertically aligned mode with a domain-divided structure and an optical compensator. This vertical-alignment-mode LCD has a wide viewing angle over 70.degree., a fast response (&lt;25 ms), and a high contrast ratio of over 300. However, it still suffers some drawbacks. For example, the formation of the two-domain structure needs the mask rubbing process, which is complicated and expensive. The rubbing process also produces ESD (Electrostatic Discharge) problem and particles. In addition, the mask rubbing will lead to a result of image sticking.